function [ code, buff ] = mx_eyelink_get_float_data( )
%MX_EYELINK_GET_FLOAT_DATA Reads the last item fetched by eyelink_get_next_data()
%  into a buffer. The event is converted to a floating-point format 
% (FSAMPLE or FEVENT). This can handle both samples and events. The buffer type 
% can be ALLF_DATA for both samples and events, FSAMPLE for a sample, or a 
% specific event buffer.
%
% Parameters:
% Returns:
% 0 if no data, SAMPLE_TYPE if sample, else event type code.
% buf 	Pointer to buffer for floating-point data: type is ALLF_DATA or FSAMPLE.
%
%----------------------------------------------------------------------------
% Copyright Eduardo Aponte 2013
% aponteeduardo@gmail.com